The influence of carotenoid and chlorophyll content on the oxidative processes in the selected vegetable oils

Abstract

Purpose: More than 100 plant species have been classified as oil products, but only a few of them are used in industrial production. In the available literature, there are no studies that would describe the relationship between the content of plant dyes and their impact on auto-oxidative processes. Therefore, this study aimed to determine dye composition and to define their effect on the acid value, peroxide value and quality assessment of selected refined and unrefined oils. Materials and methods: Twenty samples from different manufacturers were evaluated. Oils were purchased from retail trade of the Bialystok city. The total colour, acid, and peroxide values were determined in accordance with the Polish Standards PN-ISO 3960: 1996, PN-A-86934: 1995 and PN-ISO 3960: 1996, respectively. Results: Statistically significant differences of total colour values between both groups were found (p=0.002). The acid value of refined oils was lower than in an unrefined group (p=0.02). A positive statistically significant correlation was noticed between the total colour value and the acid value in the refined group (R=0.65, p=0.04). No significant effect of plant dyes on the acid or peroxide value of unrefined oils was observed. Conclusions: Refined and unrefined oils purchased in the city of Bialystok mostly met the standard values with the exception of cold-pressed oil from black cumin seeds, where the acid and peroxide value exceeded the values set in Codex Alimentarius.

Enrichment of Sunflower Oil with Ultrasound-Assisted Extracted Bioactive Compounds from Crithmum maritimum L.

“…While chlorophylls may act as prooxidants, carotenoids have antioxidant activity. Therefore, it is important to quantify them and understand how they behave when incorporated in a food matrix [27].…”

Bleaching techniques impact on some quality parameters in two different cold‐pressed oils obtained at farm scale

“…Some of these, mainly chlorophylls in hemp oil, are undesirable pigments as they lower the oil quality by affecting color, flavor, clarity, nutritional value and oxidative stability. Indeed, the stability of vegetable oils depends on various influences, but mainly on their fatty acid composition, the amount of natural antioxidants, the presence of oxygen and different storage conditions (Liang et al, 2015(Liang et al, , 2018Mahoney et al, 2018;Tura et al, 2022). Chlorophylls, fat-soluble pigments present in many raw vegetable oils, especially in hempseed oils, are undesirable compounds, because they are retained in the oil during cold pressing, making it dark and giving it an unpleasant taste, and acting as a pro-oxidant in oils exposed to light.…”

“…Oxidation of oils and fats causes a rapid deterioration of their sensory and functional properties and leads to a reduction in their nutritional value; this also hastens rancidity and may result in a rancid aroma and off flavors (Aladić, 2015; Izzo et al, 2020; Tarchoune et al, 2019). In general, the chlorophyll content in linseed oil is low if compared with other seed oils, although a certain variability linked to specific varieties was found, highlighted by a different oil color (Mahoney et al, 2018; Suri et al, 2020). On the other hand, several studies have shown that linseed oil is rich in some compounds, such as tocopherol and carotenoids which exhibit strong antioxidant properties, protecting the oil from oxidation as well as providing health benefits to humans (Liang et al, 2015; Tura et al, 2022).…”